Noise from phono. Help please.


Recently became an analog fan and currently experimenting with different phono stages (ASR basis excl., ARC Ph7 and ayre p5xe.) System includes Avid Acutus, triplanar arm which comes with RCA connectors and ground wire. ARC ref3 preamp, VAC amp and Avalon speakers. System is quiet with cds but when a phono was added, noise became an issue.

The Ayre is very quiet and there is very faint background noise that is not audible at 8-10ft from speakers. (Vahalla XLR to ARC preamp) IC position doesnot change noise level.

ARC ph7 has some noise (buzz, hum). It is audible when no music is playing but when music is playing it is not an issue. What is strange is that when I change the position of the interconnect (single ended Cardas) connecting the phono to pre, the amplitude of the noise increase and decrease markedly. The PH7 is quieter at my friend's system in a dedicated circuit.

Noise is loudest with the ASR, amplitude varies with the positioning of the phono cable, interconnect. Interestingly, when I was leaning over the ASR phono, noise also decreased. Noise is present even when the tonearm is unplugged from the phono. Noise doesnot change with shunyata hydra in or out. I used to have a Hovland preamp which had a low level hum which completely went away when RF filter was installed by Hovland.

Guys, please advise me on how to reduce hum/buzz.

1) IS this due to RF from the powerlines (needs dedicated circuit ) or is it from RF in the air?

2) How can I shield RF in the air?

3) Is the RF picked up in the tonearm cable, phono stage or interconnect? I assume that the main culprit is the IC and possibly the phonostage because when tonearm cable is unplugged, noise is still there?

4) Is grounding issue involved?

thanks in advance
128x128glai

Showing 1 response by mijostyn

Glai, give all your equipment the same ground by plugging everything into the same power strip. The only exception I make is for large power amps which I like to have dedicated lines for. If you have a lot of money a Shunyata is fine. Next make sure your tonearm ground is separate from the turntables motor ground. Motor ground should go to the power strip. Tonearm ground to the phono preamp. You may need to check this with a meter. See what the noise is like with and without turntable and tonearm grounds. Next except for the phono amp and preamp unplug each piece of equipment one at a time to see if the noise disappears. Is it a noisy tube? You have to get super low noise versions of first your phono amp then Preamp tubes to figure this out. I get mine from RAM Labs (The Tube Store) Next is the noise coming from within your house or outside your house. Run around your house unplugging stuff. Then you have to unplug your neighbors or put your stuff on an isolation transformer. Are you crazy yet? I suppose I am a very lucky guy. When I built my house the electric company forced me into buying my own power isolation Transformer, one of those big green things they park on your lawn  that your wife spends the rest of your money on trying to hide. I put a three phase converter in the house to power the shop and they were worried I'd drive the rest of the block crazy. Funny thing is I can turn on the entire shop and the Hi Fi stays dead quiet. Oh yes there is a little noise through the phono amp if you turn the volume all the way up. This is normal.